To get the most out of this book

You won't need too much hardware to set up Hadoop. The minimum setup is a single machine / virtual machine, and the recommended setup is three machines.

It is better to have some hands-on experience of writing and running basic programs in Java, as well as some experience of using developer tools such as Eclipse.

Download the example code files

You can download the example code files for this book from your account at www.packt.com. If you purchased this book elsewhere, you can visit www.packt.com/support and register to have the files emailed directly to you.

You can download the code files by following these steps:

1. Log in or register at www.packt.com.
2. Select the SUPPORT tab.
3. Click on Code Downloads & Errata.
4. Enter the name of the book in the Search box and follow the on screen instructions.

Once the file is downloaded, please make sure that you unzip or extract the folder using the latest version of:

• WinRAR/7-Zip for Windows
• Zipeg/iZip/UnRarX for Mac
• 7-Zip/PeaZip for Linux

The code bundle for the book is also hosted on GitHub at https://github.com/PacktPublishing/Mastering-Hadoop-3. In case there's an update to the code, it will be updated on the existing GitHub repository.

We also have other code bundles from our rich catalog of books and videos available at https://github.com/PacktPublishing/. Check them out!

Download the color images

We also provide a PDF file that has color images of the screenshots/diagrams used in this book. You can download it here: https://www.packtpub.com/sites/default/files/downloads/9781788620444_ColorImages.pdf.

Code in action

Visit the following link to check out videos of the code being run:
http://bit.ly/2XvW2SD

Conventions used

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "Mount the downloaded WebStorm-10*.dmg disk image file as another disk in your system."

A block of code is set as follows:

 <property>
         <name>dfs.ha.namenodes.mycluster</name>
         <value>nn1,nn2,nn3</value>
       </property>

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

 <property>
         <name>dfs.ha.namenodes.mycluster</name>
         <value>nn1,nn2,nn3</value>
       </property>

Any command-line input or output is written as follows:

      hdfs dfsadmin -fetchImage /home/packt

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "Select System info from the Administration panel."

Warnings or important notes appear like this.

Tips and tricks appear like this.